From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753708AbZHMItj (ORCPT ); Thu, 13 Aug 2009 04:49:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753588AbZHMItj (ORCPT ); Thu, 13 Aug 2009 04:49:39 -0400 Received: from casper.infradead.org ([85.118.1.10]:56521 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753537AbZHMIti (ORCPT ); Thu, 13 Aug 2009 04:49:38 -0400 Subject: Re: [RFC patch] init default dma_ops to prepare intel_iommu_init failure From: David Woodhouse To: Luming Yu Cc: FUJITA Tomonori , fenghua.yu@intel.com, tony.luck@intel.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org In-Reply-To: <3877989d0908130111m1a7d8625ha84ed1732a7eae81@mail.gmail.com> References: <3877989d0908130003i295cc7f2q343ad2446d0d51ff@mail.gmail.com> <20090813161407A.fujita.tomonori@lab.ntt.co.jp> <3877989d0908130037j5f9b1594q61e51c544a254b68@mail.gmail.com> <20090813170227V.fujita.tomonori@lab.ntt.co.jp> <3877989d0908130111m1a7d8625ha84ed1732a7eae81@mail.gmail.com> Content-Type: text/plain Date: Thu, 13 Aug 2009 09:49:33 +0100 Message-Id: <1250153373.29180.225.camel@macbook.infradead.org> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 (2.26.3-1.fc11) Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2009-08-13 at 16:11 +0800, Luming Yu wrote: > I treat this as -32 or -33 stuff, because I don't see a real system is blocking > on the problem. I found this problem when I was trying to disable some drhd > for debugging a real iommu issue...that one has priority. (The real bug you were chasing is fixed, isn't it? Or worked around, at least, since the BIOS in question is still closed source and broken.) But by talking about disabling _some_ drhd units, you've just reminded me that the problem is far more interesting -- we can have the IOMMU active for _some_ devices but not others. I was toying with the idea of putting the intel_dma_ops into dev->archdata for each pci device at boot or hotplug time, and leaving the global variable alone. We can calculate the dev->iommu mapping at that point too. And we can stop being quite so broken w.r.t. PCI hotplug... -- David Woodhouse Open Source Technology Centre David.Woodhouse@intel.com Intel Corporation